This loop that requires you to login when you are already logged in happens to me when I attempt to use the CHASEBA10 discount outside of AARP search in an ingcognito tab as well. I have the Chase BA card and have a letter here from when I got it stating I can use the code until March 21, 2020. This appears to be a new bug in their system outside of anything AARP. I will call them tomorrow and see what they say.